1. The Plant Kingdom: Flowering Plants
Chapter 25

2. LEARNING OBJECTIVE 1
Summarize the features that distinguish flowering plants from gymnosperms

3. KEY TERMS ANGIOSPERM Traditional name for flowering plants
A large, diverse phylum of plants that form flowers for sexual reproduction and produce seeds enclosed in fruits

4. Flowering Plants Like gymnosperms: Unlike gymnosperms:
Flowering plants have vascular tissues and produce seeds
Unlike gymnosperms:
Ovules of flowering plants are enclosed within an ovary

5. KEY TERMS
OVULE
Structure in the ovary that contains a female gametophyte and develops into a seed after fertilization
OVARY
Base of a carpel or fused carpels that contains ovules and develops into a fruit after fertilization

6. Orange Fruit Development

7. LEARNING OBJECTIVE 2
Describe the ecological and economic significance of the flowering plants

8. Ecology and Economy
Our survival as a species depends on flowering plants
Major food crops
Products
Cork, rubber, tobacco, coffee, chocolate, aromatic oils for perfumes
Valuable lumber
Fibers and medicines

9. Economic Botany
Subdiscipline of botany that deals with plants of economic importance
Most of these are flowering plants

10. LEARNING OBJECTIVE 3
Distinguish between monocots and eudicots, the two largest classes of flowering plants
Give specific examples of each class

11. KEY TERMS
COTYLEDON
The seed leaf of a plant embryo, which may contain food stored for germination

12. KEY TERMS
MONOCOT
One of two main classes of flowering plants; monocot seeds contain a single cotyledon
Monocots have floral parts in threes
Monocots include grasses, orchids, irises, onions, lilies, palms

13. KEY TERMS
EUDICOT
One of two main classes of flowering plants; eudicot seeds contain two cotyledons
Eudicots have floral parts in fours or fives
Eudicots include oaks, roses, mustards, cacti, blueberries, sunflowers

14. Monocots and Eudicots

15. (a) Monocots, such as this nodding trillium
Petal
Sepal
Anther of
stamen
Stigmas of
pistil
Figure 25.2: The two largest classes of flowering plants.
(a) Monocots, such as this nodding trillium
(Trillium cernuum), have their floral parts in threes.
Note the three green sepals, three white petals, six
stamens, and three stigmas (the compound pistil
consists of three fused carpels).
Fig. 25-2a, p. 488

16. (b) Most eudicots such as this Tacitus
Petal
Anther of
stamen
Pistils
Figure 25.2: The two largest classes of flowering plants.
(b) Most eudicots such as this Tacitus
bellus have floral parts in fours or fives.
Note the five petals, 10 stamens, and five
separate pistils. Five sepals are also present
but barely visible against the background.
Fig. 25-2b, p. 488

17. LEARNING OBJECTIVE 4
Briefly explain the life cycle of a flowering plant
Describe double fertilization

18. Life Cycle Flowering plants undergo an alternation of generations:
Sporophyte generation is larger and nutritionally independent
Gametophyte generation is reduced to only a few microscopic cells

19. KEY TERMS DOUBLE FERTILIZATION
A process in the flowering plant life cycle in which there are two fertilizations
One results in formation of a zygote
Second results in formation of endosperm

20. KEY TERMS
ENDOSPERM
The 3n nutritive tissue formed at some point in the development of all angiosperm seeds

21. Life Cycle: Flowering Plants

22. 6 5 3 7 2 4 8 1 Pollination Developing pollen tube of mature
male gametophyte
Each microspore
develops into a
pollen grain 6
Embryo sac (mature
female gametophyte) 5
Pollen grain
(immature male
gametophyte)
Microspore
Tetrad of
microspores
Pollen
tube 3
Polar
nuclei
Megaspore
Egg
nucleus
Two sperm
cells
HAPLOID (n)
GAMETOPHYTE
GENERATION
Meiosis
Ovary
Double fertilization
DIPLOID (2n)
SPOROPHYTE
GENERATION
Megaspore mother cell
Endosperm (3n) 7 2 4
Zygote (2n)
Megasporangium
(ovule)
Figure 25.3: A generalized life cycle of flowering plants.
The most distinctive feature of the flowering plant life cycle is double fertilization, in which one sperm cell unites with the egg to form a zygote, and the other sperm cell unites with the two polar nuclei to form a 3n cell that gives rise to endosperm. See text for a detailed description.
Fruit 8
Embryo
Seed
Microspore mother
cells within
microsporangia
Seed coat 1
Seedling
Anther
Flower of mature
sporophyte
Fig. 25-3, p. 490

23. Pollen Grains

24. LEARNING OBJECTIVE 5
Discuss some of the evolutionary adaptations of flowering plants

25. Adaptations of Flowering Plants 1
Reproduce sexually by forming flowers
Form seeds within fruits after double fertilization

26. Adaptations of Flowering Plants 2
Have efficient water-conducting vessel elements in xylem and carbohydrate-conducting sieve-tube elements in phloem
Have pollen grains transported by wind, water, insects, other animals

27. KEY TERMS
APOMIXIS
A type of reproduction in which fruits and seeds are formed asexually

28. Adaptability of Flowering Plants

29. LEARNING OBJECTIVE 6
Trace the evolution of flowering plants from gymnosperms

30. Evolution of Flowering Plants
Probably descended from ancient gymnosperms with specialized features
leaves with broad, expanded blades and closed carpels
Probably arose only once

31. Drimys piperita Carpel

32. (a) The carpel resembles a folded leaf in which the ovules borne on
Fused
margin
Ovules
Stigma
Ovary
Style
Figure 25.6: Carpel of Drimys piperita.
Stigma
(a) The carpel resembles a folded
leaf in which the ovules borne on
its upper surface are enclosed.
(b) A cross section of the
carpel, cut along the dashed
line in (a).
Fig. 25-6, p. 493

33. Fossil Angiosperms

34. Pistils Scars on reproductive axis Carpel Ovule
Figure 25.7: Fossil angiosperms.
(a) The oldest known fossil angiosperm. This fossil of
the extinct plant Archaefructus shows a carpel-bearing
stem. It was discovered in northeastern China and is
about 125 million years old.
(b) The fossilized flower of the extinct plant Archaeanthus
linnenbergeri, which lived about 100 mya. The
scars on the reproductive axis (receptacle) may show
where stamens, petals, and sepals were originally
attached but abscised (fell off). Many spirally arranged
pistils were still attached at the time this flower was
fossilized.
Fig. 25-7, p. 494

35. Evolution of Flowering Plants

36. Basal Angiosperms Core Angiosperms Evolution of vessel elements
Amborella
Water lilies
Star anise
Magnoliids
Monocots
Eudicots
Evolution of
vessel elements
Evolution of
flowering plants
(a) One hypothesis of relationships among the flowering plants, based on fossil and molecular evidence. Amborella, water lilies, and star anise are living plants
whose ancestors apparently branched off the angiosperm family tree early. These early groups were followed by the magnoliids, the monocot branch, and the eudicots.
Figure 25.8: Evolution of flowering plants.
Fig. 25-8, p. 495

37. LEARNING OBJECTIVE 7
Distinguish between basal angiosperms and core angiosperms

38. KEY TERMS BASAL ANGIOSPERM CORE ANGIOSPERM
One of three groups of angiosperms thought to be ancestral to all other flowering plants
CORE ANGIOSPERM
Group including most angiosperm species
Divided into three subgroups: magnoliids, monocots, and eudicots

39. KEY TERMS MAGNOLIID One of the groups of flowering plants
Core angiosperms once classified as “dicots,” but molecular evidence indicates they are neither eudicots nor monocots
Includes species in magnolia, laurel, and black pepper families, several related families

40. LEARNING OBJECTIVE 8
Briefly describe the distinguishing characteristics and give an example or two of each of the following flowering plant families: magnolia, walnut, cactus, mustard, rose, pea, potato, pumpkin, sunflower, grass, orchid, and agave

41. Flowering Plant Families 1
More than 300 families
Magnolia family
Important ornamentals and source of timber
Examples: southern magnolia, tuliptree

42. Magnolia Family

43. Figure 25.9: The magnolia family.
Fig. 25-9, p. 497

44. Flowering Plant Families 2
Walnut family
Provides nuts for food, wood for furniture
Examples: English walnut, black walnut, pecan
Cactus family
Important as ornamentals
Examples: prickly pear, Christmas cactus

45. Walnut Family

46. Female flowers Catkin of male flowers Fruit (a drupe) Young tree
Figure 25.10: The walnut family.
Fruit
(a drupe)
Young tree
Compound leaf
Fruit with husk
removed to show
hard stone
(a) The pinnately compound leaves and green fruits of black walnut (Juglans nigra) make the tree easy to recognize.
Fig a, p. 498

47. Figure 25.10: The walnut family.
Fig b, p. 498

48. Figure 25.10: The walnut family.
Fig c, p. 498

49. Cactus Family

50. (c) Cactus flowers contain numerous sepals, petals, and
Stamens
Stigma
Petals
Figure 25.11: The cactus family.
(c) Cactus flowers contain numerous sepals, petals, and
stamens. The compound pistil consists of two to many fused
carpels. In this photo of a prickly pear cactus (Opuntia
humifusa), the petals, stamens, and stigma are evident.
Fig c, p. 499

51. Flowering Plant Families 3
Mustard family
Many important food crops
Examples: cabbage, broccoli, cauliflower, turnip, mustard
Rose family
Commercially important fruits and ornamentals
Examples: apple, pear, plum, cherry, apricot, peach, strawberry, raspberry, rose

52. Mustard Family

53. (a) A typical mustard flower, showing the
Pistil
Stamen
Petal
Figure 25.12: The mustard family.
Sepal
(a) A typical mustard flower, showing the
four petals arranged in the shape of a cross.
Fig a, p. 501

54. Mustard Family

55. Mustard Family

56. Mustard Family

57. Rose Family

58. Rose Family

59. Rose Family

60. Flowering Plant Families 4
Pea family
Important food crops
Examples: garden pea, chick pea, green bean, soybean, lima bean, peanut, red clover, alfalfa

61. Pea Family

62. (b) Close-up of a bean flower, showing its irregular corolla shape.
Compound leaf
(three leaflets)
Banner
Young
fruit
Wing
Sepal
Corolla
Keel (two
fused petals)
(b) Close-up of a bean flower, showing
its irregular corolla shape.
Pod (fruit)
Remnants of
stigma and style
Seeds
Remnants of sepals
(and sometimes petals
and stamens)
Figure 25.14: The pea family.
(c) The bean fruit, a legume, is opened to show the seeds.
(a) Part of a common bean (Phaseolus vulgaris)
plant, showing flowers and developing fruits.
Fig a-c, p. 503

63. Pea Family

64. Pea Family

65. Flowering Plant Families 5
Potato family
Important food crops and chemicals used as drugs
Examples: potato, tomato, green pepper, eggplant, petunia, deadly nightshade (belladonna)

66. Potato Family

67. Flowering Plant Families 6
Pumpkin family
Food crops
Examples: pumpkins, melons, squashes, cucumbers, cantaloupe, honeydew, muskmelon, cucumber, watermelon

68. Pumpkin Family

69. (a) Cutaway view of a female squash flower. Note
Petals
fused into
bell shape
Stigma
Style
Ovary
Figure 25.16: The pumpkin family.
(a) Cutaway view of a female squash flower. Note
the inferior ovary located beneath the point of
attachment of the sepals and petals.
Fig a, p. 505

70. Pumpkin Family

71. (b) Cutaway view of a male squash flower. Note the united anthers.
Figure 25.16: The pumpkin family.
(b) Cutaway view of a male squash flower. Note
the united anthers.
Fig b, p. 505

72. Pumpkin Family

73. Flowering Plant Families 7
Sunflower family
One of the largest families of flowering plants
Examples: chrysanthemums, marigolds, sunflowers, daisies, and some food plants such as lettuce, globe artichokes

74. Sunflower Family

75. a) Head of a sunflower (Helianthus annuus).
Ray floret
Disc floret
Figure 25.17: The sunflower family.
a) Head of a sunflower (Helianthus annuus).
Fig a, p. 506

76. (d) Bisexual disc floret.
Ray floret
Disc floret
Stigmas
Anther
Corolla
Figure 25.17: The sunflower family.
Ovary
(c) Female ray floret.
(d) Bisexual disc floret.
Fig cd, p. 506

77. Flowering Plant Families 8
Grass family
Most important family of flowering plants from the human standpoint
Examples: rice, wheat, corn, oats, barley, rye, sugarcane, bamboo

78. Grass Family

79. are wind pollinated, are highly modified. Note, for example, the long,
Anther
Inflorescence
Palea
Filament
Feathery
stigma
Ovary
Blade
Reduced petals
Sheath
Lemma
Stolon
Rhizome
Figure 25.18: The grass family.
Fibrous root
system
(a) The growth habit of a representative grass plant. Grass flowers, which
are wind pollinated, are highly modified. Note, for example, the long,
feathery stigmas, adapted to efficiently catch wind-borne pollen.
Fig a, p. 507

80. Flowering Plant Families 9
Orchid family
One of the largest families of flowering plants; contains a greater variety of flowers than any other family
Example: the vanilla orchid
Agave family
Best known for ornamentals
Examples: century plant, sisal hemp, bowstring hemp

81. Orchid Family

82. (a) The moth orchid (Phalaenopsis hybrid)
Aerial roots
Figure 25.19: The orchid family.
(a) The moth orchid (Phalaenopsis hybrid)
has photosynthetic aerial roots.
Fig a, p. 509

83. (b) A Cymbidium hybrid has pseudobulbs
Figure 25.19: The orchid family.
(b) A Cymbidium hybrid has pseudobulbs
that function as storage organs.
Fig b, p. 509

84. (c) Orchid flowers, such as Dendrobium, are
Petal
Sepal
Lip (modified
petal)
Figure 25.19: The orchid family.
(c) Orchid flowers, such as Dendrobium, are
distinctive in that the third petal forms a lip.
Fig c, p. 509

85. Agave Family

86. Animation: Monocot Life Cycle
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